FIG. 12 is a sectional view of a conventional motor, and FIG. 13 shows a stator of the motor of FIG. 12. The motor has a wound rotor 12 including a commutator 14 and a permanent magnet stator 11. The rotor is supported by bearings 15 fixed to end caps 16 which close open ends of the stator. Brush gear 17 supported by one of the end caps transfers electrical power from motor terminals (not shown) to the rotor windings 13 via the commutator 14. As shown in FIG. 13, the stator comprises a stator housing 40, a plurality of magnet brackets 32 and a plurality of magnets 30. During the manufacturing process, the magnets 30 are arrayed onto an inner surface of the housing 40, and then the magnet brackets 32 are press-fitted into the space between adjacent magnets 30 so that the magnet brackets 32 urge the magnets in two circumferential directions and then the brackets 32 are fixed to the inner surface of the housing 40. One disadvantage of the conventional motor is that the stator housing 40 is vulnerable to being deformed during the process of inserting or fixing the magnet brackets 32, and the magnets 30 are vulnerable to being moved during the process too.
Furthermore, in some cases the space between adjacent magnets is too narrow to insert and fix a magnet bracket. Therefore, the magnets are glued to the inner surface of the stator housing. The magnets are vulnerable to being detached from the housing since the magnets are not retained by any magnet bracket and the strength of the glue may deteriorate with age and exposure to the elements.